1: 1) NaH / 1) THF 2: NaBH4 / methanol / -25 °C 3: 65percent aq. acetic acid / tetrahydrofuran / 50 °C 4: 82 percent / imidazole / dimethylformamide / 23 °C 5: 33 percent / H2 / (methyl benzoate)*Cr(CO)3 / acetone / 15 h / 120 °C / 51485.6 Torr 6: 88 percent / tetrabutylammonium fluoride (TBAF) / tetrahydrofuran / 23 °C 7: 100 percent / 10percent aq. NaOH / methanol / 0 °C View Scheme

1: methanephosphonic acid dimethyl ester With n-butyllithium in tetrahydrofuran; hexane T=-78°C; 0.5 h; 2: methyl 2-methyl-4-hexynate in tetrahydrofuran; hexane T=-78 - 20°C; 4 h;

1: methanephosphonic acid dimethyl ester With n-butyllithium in tetrahydrofuran; hexane T=-78°C; 1 h; 2: (+/-)-2-methylhex-4-ynoic acid ethyl ester in tetrahydrofuran; hexane T=-78°C; 3 h;

hydrogenchloride; n-butyllithium; sodium chloride; oxalic acid; diisopropylamine in tetrahydrofuran; N,N,N',N',N'',N''-hexamethylphosphoric triamide; water; propionic acid; pentane

1: diethyl ether 2: 1.) n-BuLi / 1.) THF, -78 deg C, 20 min, 2.) THF, -78 deg C, 15 min; room temperature, 1 h View Scheme

1.1: lithium chloride / water; dimethyl sulfoxide / 160 °C 2.1: n-butyllithium / tetrahydrofuran; hexane / 1 h / -78 °C 2.2: 3 h / -78 °C View Scheme

Multistep reaction;